This invention pertains to a controlled levitation vehicle that is designed so that the vehicle levitation and stop times can be shortened.
Vehicles that are levitated on air include rope shuttles where the vehicle is towed by a rope, and linear shuttles where the vehicle is driven by a linear motor.
A rope shuttle, as shown in FIGS. 8a and 8b, is furnished with levitation apparatus 2a on the bottom part of shuttle vehicle 1. Levitation apparatus 2a comprises blower 4 that is driven by a motor 3, many air pads 8, duct 5 and a hose 6 that connect the air pads 8 and a blower 4. It is constituted so that vehicle 1 is made to levitate above track or roadway 9 by supplying air from blower 4 to air pads 8.
Tow device 10 that moves vehicle 1 is furnished with winch 11 and pulleys 12 and 13 in one tow section and is equipped with pulleys 14 and 15 and a weight 18 in the other. Wire rope 16 runs endlessly on cable wheel 11a, pulleys 12, 14, and 13, and cable wheel 11a of winch 11 in that order. The other end of wire rope 17 that is connected to pulley 14 is connected to weight (or hydraulic system) 18 via pulley 15. Tension is applied to pulley 14 in the direction of pulley 15 by the force of weight 18, and rope 16 is attached to wire rope attachment arm 19 furnished for wire rope 16 and vehicle 1.
When vehicle 1 is moved, the vehicle is made to levitate above track 9 by levitation apparatus 2a. Winch 11 is driven while vehicle 1 is levitated, vehicle 1 is towed by rope 16, and vehicle 1 is moved without any frictional resistance between vehicle 1 and track 9.
A linear shuttle levitation apparatus, as shown in FIG. 2, comprises air pads 8 attached to chassis 7 of vehicle 1. Chassis 7 is used as an air distribution duct to air pads 8 so that air is supplied to air pads 8 via duct 5 and chassis 7 from blower 4.
The linear induction motor of a linear shuttle, as shown in FIGS. 1a and 1b, is constituted with the primary side (primary core and primary coil) 21 of the linear induction motor being furnished on the bottom part of vehicle 1 and secondary side (conductor) 22 being placed on track 9.
When the vehicle is moved, vehicle 1 is made to levitate by levitation apparatus 2. While vehicle 1 is levitated, a three-phase power source is connected to the linear motor, a moving magnetic field is generated on primary side 21, and vehicle 1 is moved by means of the electromagnetic force resulting when a secondary current is generated by this magnetic field on the secondary side, producing thrust. When vehicle 1 is moved in two directions, the phase sequence of the three-phase power source input to the linear induction motor can be reversed.
With a rope shuttle, the vehicle is coupled to a rope, so by operating a brake attached to the winch the vehicle can be held in place and stopped at a station while the vehicle remains levitated. However, in the case of a linear shuttle, the linear motor that drives the vehicle is self-propelled and mounted to the vehicle, so the vehicle cannot be held still while it remains levitated. This can be solved by furnishing a separate brake apparatus, but as the number of components increases, the rate of breakdowns also rises.
As shown in FIG. 3, the shuttle brake comprises brake skid 23, furnished on the bottom of the vehicle that touches the surface of track 9 when levitation ceases, thereby stopping vehicle 1 by the friction between brake skid 23 and track 9. In this arrangement, the vehicle drops and the brake skid engages due to the cutting off of the air sent to the air pads of the levitation apparatus.
In the past, motor 3 of blower 4 would have been turned on and off to shut off air to air pads 8, so the blower rotation when stopped at the station would be zero. Time would therefore be required to restart the blower, and as a result, passengers would have to wait, and the number of operation cycles (headway frequency) could not be increased.
This invention was devised with the aforementioned problems of linear shuttles in mind. Its purpose is to provide a controlled levitation vehicle that will permit the vehicle to re-levitate rapidly after the vehicle has stopped levitation and has been held on the track by the brake skid.
According to the present invention, a levitation vehicle is equipped with a levitation apparatus that has a blower driven by a motor, multiple air pads are furnished for a chassis that also serves as a duct connected to the blower, and damper valves are furnished for the discharge side of the blower and for the chassis, and a brake skid is attached to the undersurface of the chassis. The vehicle is further equipped with an inverter that operates the blower motor, a means that makes the blower discharge damper valve close when starting and that also regulates the output of the inverter to the standby output, a means that makes the chassis damper valve close when there is an instruction to levitate and that also regulates the output of the inverter to the levitation output, and a means that returns the output of the inverter to the standby state when there is an instruction to land and that also makes the blower discharge damper valve open. Time required for the vehicle to levitate and to stop will be shortened.